docs: def _tle_to_keplerian_mean(cls, coord, center):
          """Conversion from the TLE standard format to the Mean Keplerian
  
          see :py:class:`Tle` for more information.
          """
          i, Ω, e, ω, M, n = coord
          a = (center.µ / n ** 2) ** (1 / 3)
  
          return np.array([a, e, i, Ω, ω, M], dtype=float)